Every evolved trait has a cost. We as a civilization have certainly been careless with, say, antibiotic resistance. If we stopped using a certain antibiotic tomorrow and didn't start using it for another 50 years, we'd find that most if not all of the resistant bacteria would've lost that resistance as they'd evolved new traits.

I'm reminded of the pronghorn antelope, a herbivore that evolved fast speed to avoid a predator that no longer exists, a cat having died out 7000+ years ago. It still has that speed but it has a real cost to their metabolism and their need to constantly eat. at some point they're going to lose that if it's not reinforced by some new predator or other evolutionary advantage.